How quickly can I lower Alk?

[TheJoshuaPlan]

Currently have an alkalinity level of 11dkh and I would like to lower that down to roughly 9. I use about 1 dkh daily right now. My plan was to turn off the calcium reactor for about a day or 2 and let it drop down then turn it back on to start putting back in the 1dkh a day my reactor is currently producing. My question is is this too quick to lower the alkalinity?

Thanks,
JS

 

[Randy Holmes-Farley Verified Community Expert]

I'd let it drop over a period of about 4-5 days. There is no rush.

 

[TheJoshuaPlan]

I'd let it drop over a period of about 4-5 days. There is no rush.

That means I would need to lower the DKH output of the reactor so that it only puts out about half of what it currently does. I could do that, but I had everything setup perfect for the reactor to equal the coral intake. Second option would be to use DIY 2 part to stretch out the drop to 9 dkh over the 4-5 days you suggest.

 

[Brett S]

Nothing good happens quickly in reefing. If your corals are used to 11dkh you’re only going to cause problems by trying to drop it quickly. Maybe I’m too conservative, but I would probably stretch out a 2dkh drop like that over several weeks, especially if I had been running at 11 for a while.

 

[DC Reefer]

That means I would need to lower the DKH output of the reactor so that it only puts out about half of what it currently does. I could do that, but I had everything setup perfect for the reactor to equal the coral intake. Second option would be to use DIY 2 part to stretch out the drop to 9 dkh over the 4-5 days you suggest.

you could also run the reactor 12-18 hours/day until your Alk is where you want it and then run it 24/7.

 

[KrisReef]

you could also run the reactor 12-18 hours/day until your Alk is where you want it and then run it 24/7.

^ I wished I had thought of that! ^
Thanks for posting it!

 

[14 foot reef]

That means I would need to lower the DKH output of the reactor so that it only puts out about half of what it currently does. I could do that, but I had everything setup perfect for the reactor to equal the coral intake. Second option would be to use DIY 2 part to stretch out the drop to 9 dkh over the 4-5 days you suggest.

If your reactor was set up perfectly and you want your DKH to be 9 how did it get to 11. Are you adding something else to raise the DKH, if so, I would just stop that and let it come down on its own, and leave Calcium Reactor set as is.

 

[Sisterlimonpot]

That means I would need to lower the DKH output of the reactor so that it only puts out about half of what it currently does. I could do that, but I had everything setup perfect for the reactor to equal the coral intake. Second option would be to use DIY 2 part to stretch out the drop to 9 dkh over the 4-5 days you suggest.

How are you controlling the effluent? are you using a probe to maintain pH inside the reactor?

There are 2 easy ways to lower alk, change effluent speed or raise pH inside the reactor.

If you have a means to control effluent you can slow the speed of the pump and measure your tanks dkh to make sure you didn't slow it down too much, unless you have a legitimate reason to lower it quickly, I would make subtle changes and let it drop slowly.

If you have a means to control reactor pH, you can simply raise the pH inside the reactor and monitor as instructed above. this can also be achieved by slowing down your bubble count or gas pressure.

These are generic suggestions, if you give more detail of what you have control of and what your reactor is currently set to, you can get more specific ways to do it gradually.

 

[TheJoshuaPlan]

If your reactor was set up perfectly and you want your DKH to be 9 how did it get to 11. Are you adding something else to raise the DKH, if so, I would just stop that and let it come down on its own, and leave Calcium Reactor set as is.

Great question. It happened because I set my reactor too high of effluent output and jumped up way too fast. I had it at 9 dkh previously until I messed that up, now just trying to get it back.

 

[TheJoshuaPlan]

How are you controlling the effluent? are you using a probe to maintain pH inside the reactor?

There are 2 easy ways to lower alk, change effluent speed or raise pH inside the reactor.

If you have a means to control effluent you can slow the speed of the pump and measure your tanks dkh to make sure you didn't slow it down too much, unless you have a legitimate reason to lower it quickly, I would make subtle changes and let it drop slowly.

If you have a means to control reactor pH, you can simply raise the pH inside the reactor and monitor as instructed above. this can also be achieved by slowing down your bubble count or gas pressure.

These are generic suggestions, if you give more detail of what you have control of and what your reactor is currently set to, you can get more specific ways to do it gradually.

I use a medical pump for controlling the amount of effluent that comes out of the reactor, this is set to 5ml/min. I also have a really nice C02 regulator that I built that is rock solid. I set the bubble count and the effluent output to match the DKH of the coral uptake. I do not use a ph probe as of right now to shutoff the C02 if the ph gets too low in the reactor, it just stays rock solid. I have a hand held PH tester that I test the effluent output regularly and it stays at 7.0 ph. I pretty much test this daily as of late. I do have an APEX that I could use to turn off the C02 and the medical pump for effluent flow for like 8 hours a day until I get down to where I want my DKH to be. Hope that helps with what I am using.

 

[Sisterlimonpot]

I use a medical pump for controlling the amount of effluent that comes out of the reactor, this is set to 5ml/min. I also have a really nice C02 regulator that I built that is rock solid. I set the bubble count and the effluent output to match the DKH of the coral uptake. I do not use a ph probe as of right now to shutoff the C02 if the ph gets too low in the reactor, it just stays rock solid. I have a hand held PH tester that I test the effluent output regularly and it stays at 7.0 ph. I pretty much test this daily as of late. I do have an APEX that I could use to turn off the C02 and the medical pump for effluent flow for like 8 hours a day until I get down to where I want my DKH to be. Hope that helps with what I am using.

Perfect! Thanks. Just for simplicity, I would slow the peristaltic pump to 1 - 2 ml/min and monitor.

Although, at that effluent rate and pH I would guess that tou don't have a bunch of big colonies, and you can simply do what you suggested and shut off the Co2 solenoid and PeriPump and monitor as well.

 

[Randy Holmes-Farley Verified Community Expert]

While I have never used a CO2 reactor, I'd be more inclined to leave the flow unchanged and reduce the CO2. That will dissolve less.

It is not clear to me that reducing the flow rate will necessarily cause less dissolution of CaCO3 with a fixed addition of CO2.

 

[TheJoshuaPlan]

Perfect! Thanks. Just for simplicity, I would slow the peristaltic pump to 1 - 2 ml/min and monitor.

Although, at that effluent rate and pH I would guess that tou don't have a bunch of big colonies, and you can simply do what you suggested and shut off the Co2 solenoid and PeriPump and monitor as well.

Only frags at this point. Really appreciate your help!

 

[TheJoshuaPlan]

While I have never used a CO2 reactor, I'd be more inclined to leave the flow unchanged and reduce the CO2. That will dissolve less.

It is not clear to me that reducing the flow rate will necessarily cause less dissolution of CaCO3 with a fixed addition of CO2.

A slower effluent rate would in theory increase the PH of the reactor being the C02 rate is the same which would dissolve the media faster. I think the best solution at this point is to turn off the effluent pump and C02 for 8 hours a day and test to see how quickly the DKH drops . One would assume it would be a 1/3 dkh per day, but I've read corals use more alkalinity and calcium while the lights are on. This will be an interesting test.

 

[Sisterlimonpot]

While I have never used a CO2 reactor, I'd be more inclined to leave the flow unchanged and reduce the CO2. That will dissolve less.

It is not clear to me that reducing the flow rate will necessarily cause less dissolution of CaCO3 with a fixed addition of CO2.

That's an excellent point. Without a pH probe to turn off the Co2 flow, it may work against you.

 

[Randy Holmes-Farley Verified Community Expert]

A slower effluent rate would in theory increase the PH of the reactor being the C02 rate is the same which would dissolve the media faster.

You mean decrease the pH, right?

 

[TheJoshuaPlan]

You mean decrease the pH, right?

Yes thank you

 

[TheJoshuaPlan]

Apex is setup to turnoff reactor feed and C02 from 4am until noon when the lights come on. I’ll let you know how it goes.

 

[vetteguy53081]

The definition of quickly in reefing is: SLOWLY

 

[Doctorgori]

I could be wrong but I’ve killed plenty of corals and I’d bet alk swings did a few.
Nobody wants to fess up numbers but I’d risk .1 DKH/day or .5/week ...
but Then again I don’t own any Walt Disney-ish stuff
Also I thought thin skeleton stuff like Montis show alk stress 1st ... I won’t argue conflicting info